The present invention relates to the contactless comminution of concrements in the body of a living being under utilization of shock waves using particularly a source in which shock waves are generated, a focusing reflector and a system or device for locating concrements in the body. Furthermore a rest for the patient is to be provided.
German Pat. No. 2,351,247 corresponding to U.S. Pat. No. 3,942,531 discloses a device for comminution of concrements in the body of a living being using a focusing chamber constructed as a portion of a rotational ellipsoid having two focal points; in one of the focal points shock waves are generated through spark discharge while the device as such is positioned with respect to the body of the living being so that the second focal point coincides with the previously located concrements such as a kidney stone. Such a device then permits the comminution of kidney stones in a non-invasive manner, not even requiring the insertion of probes.
The socalled kidney lithotripter made and installed since 1983 by Dornier System GmbH includes two X-ray imaging systems for localizing and pinpointing the location of a kidney stone basically by triangulation and ascertaining at the same time the size of that stone. The kidney lithotripter proper is then positioned and triggered and the focused shock waves comminute the kidney stone to obtain a rather fine grain grit, which will subsequently be discharged from the body in a natural manner.
The device for generating the shock waves, or field of shock waves, and the device or devices for locating the kidney stone are arranged so that they do not mutually interfere. Basically one uses two X-ray devices for stereoscopically locating the kidney stone and they are placed to both sides of the shock waves generator and reflector (see e.g. "Dornier Kidney Lithotripter"). The two central beams of the X-ray locating devices intersect the axis on which the two focal points are located, in each instance by about 40.degree. and that intersection is of course to be right in the location of the kidney stone.
Since the kind of arrangement just described requires two separate X-ray devices it is rather expensive. Moreover, certain portions of the reflector structure have to be provided with cut-outs or the like, to permit passage of Xrays. Also a certain coupling fluid is required such as water, since from the point of generation to the point of action the shock waves should propogate through an accoustically homogeneous medium in order to avoid scatter or even unwanted ordered reflection with parasitic focussing in the wrong spot. Also, any attenuation of the shock waves is to be avoided as much as possible. The coupling water moreover is an impediment for X-rays and may require the introduction of inflatable bellows.